Slugs are the bane of gardeners’ lives, regularly topping surveys of garden pests. They munch the new growth of precious plants, demolish seedlings overnight and munch irregularly-shaped holes in leaves, stems, flowers, tubers and bulbs and potatoes, leaving their silvery slime trails behind.
Slugs are active for most of the year but are a particular problem in spring, when there’s plenty of young growth for them to eat. They are mostly active after dark, especially when it’s warm and damp. In hot, dry weather they bury themselves in the soil or hide in cool, dark places to avoid dehydrating.
There are over 40 species of slugs in the UK. Not all slugs eat live plants, however – many of the larger ones eat decaying or dead plant material and they are an important part of the composting process.
Despite your best efforts, some losses to slugs are inevitable. Accept that your garden is never going to be slug free, and find ways to work around this.
Make sure you prioritise the protection of the most vulnerable plants – all seedlings, new growth on most herbaceous plants, and all parts of especially susceptible plants such as delphiniums, hostas and dahlias. If you’re growing plants in pots, make sure there isn’t a ‘bridge’ of leaves from one plant to another, as slugs can travel from pot to pot this way.
Sow extra seeds so you have seedlings waiting in the wings to replace any that are eaten by slugs, and grow more than you need so you still have some crops left over after a slug attack. And add plenty of slug-resistant plants (see our list below) to keep damage to a minimum.
There are many options for controlling slugs. The best approach is to combine several methods, starting early in spring. Here are some ways to controlling slugs in your garden, some of them recommended in a survey of readers of BBC Gardeners’ World Magazine.
As any gardener knows, slugs and snails can wreak havoc on tender plants like balsams (Impatiens balsamina). These squishy pests use razor-sharp mouthparts to chew irregular holes in foliage and flowers overnight. Left unchecked, they can quickly defoliate plants.
The good news is balsams can be protected from slug damage with diligent monitoring and control methods. Here are effective tips for getting rid of slugs on balsam plants:
Inspect Plants Frequently
Early detection is key to protecting plants from slugs. In the morning and evening, thoroughly check the top and underside of leaves, stems, and around the base of plants for these nocturnal pests. Also scout for the telltale slime trails slugs leave behind. Catch infestations early before populations explode.
Remove Slugs Manually
Handpicking slugs and snails is an organic control method suitable for small gardens. Look for the pests under boards pots and in damp places near plants during the day when slugs are inactive. Crush larger slugs or drop them into a bucket of soapy water to kill.
Set Out Traps
Traps lure in slugs where they can be disposed of easily
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Beer traps: Set out small containers of beer at soil level near plants. Slugs are attracted to the yeasty aroma and will drown.
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Pie pans or plastic lids: Smear a thin layer of peanut butter on the interior surface. Check underneath in the mornings to remove trapped slugs.
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Damp boards or grapefruit halves: Slugs will congregate underneath these daytime shelters. Flip them over and dispose of slugs daily.
Use Natural Predators
Encourage natural slug predators to patrol your garden:
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Ground beetles: These voracious insects feast on slug eggs and young slugs. Avoid pesticides that would kill them.
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Frogs and toads: Attract them with damp areas. They’ll happily snack on slugs and insects.
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Ducks: Free range ducks will hunt for slugs and snails. Just be sure they don’t damage wanted plants!
Apply Barriers
Physical barriers can block slugs from reaching balsam’s succulent foliage:
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Copper tape: Slugs recoil from this conductive material. Wrap it around raised garden beds or pot rims.
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Diatomaceous earth: The sharp dust scrapes and dehydrates slugs. Sprinkle around plants, reapplying after rain or watering.
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Crushed eggshells: The abrasive texture deters slugs. Work into soil or mulch around plants.
Use Slug Deterrent Products
Look for OMRI certified organic commercial slug deterrents based on iron phosphate. Scatter pelleted baits or spray liquid products onto soil around plants. As slugs ingest it, they stop feeding and die within 3-6 days. Reapply as directed after rain or watering.
Modify the Environment
Make conditions less appealing for slugs:
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Eliminate damp hiding spots like weeds, piles of debris, and overly-dense ground cover.
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Allow soil to dry slightly between waterings. Slugs thrive in consistently moist conditions.
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Switch to drip irrigation instead of sprinklers to keep foliage dry.
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Raise plants up on benches or tables to make them harder to reach.
Protect Young Plants
Seedlings and freshly planted balsams are most vulnerable to slug damage. Use floating row covers or small cloches to temporarily keep slugs off until plants establish. Just remember to ventilate on sunny days to avoid overheating.
Check Potted Balsams
Slugs and snails easily climb into containers. Apply a band of petroleum jelly or double-sided tape around the inside rim of pots to block access. Or elevate pots onto trays filled with water to create a slug moat.
Remove Hiding Spots
Pots, boards, weedy areas, and dense groundcovers all provide ideal damp hiding spots for slugs during the day. Eliminate or reduce these in and around the garden to make it less hospitable.
Why Balsams Are Susceptible
Balsams have thin, tender foliage that slugs can rapidly shred. They also require consistently moist soil – perfect conditions for these soft-bodied pests. Plus slugs are most active at night when balsam’s colorful blooms are wide open and vulnerable.
By taking a proactive approach with a variety of organic control methods, you can successfully protect your balsams from slugs. Consistent monitoring and early interventions will allow you to enjoy lush, unmarred foliage and bountiful blooms all season long.
Water in the morning
This ensures that the soil has dried out by the evening, when slugs are most active. Wet soil at night can create a slug highway between plants.
Copper rings can be effective slug deterrents – if a slug tries to cross one it receives an ‘electric shock’, forcing it back. Put rings around vulnerable plants such as hostas – bury them deep as slugs may reach the plant from underneath.
Some gardeners also swear by sticking copper tape around the rim of pots, although a recent trial by the RHS found this to be ineffective. Research is ongoing, however.
- Buy copper rings from Crocus, Dobies and Suttons
How to control slugs
Ultimately, the best thing you can do to control slugs in your garden is to create a healthy ecosystem. Create lots of habitats for slug predators – hedges, shrubs (especially those with berries) and trees will all attract birds such as blackbirds and thrushes, which eat slugs (and snails). If you have room, a wildlife pond is a great addition to your garden – the newts, frogs and toads that use it will also devour slugs. Laying a slat down will attract slow worms, which eat a lot of slugs. Encourage wildlife in to your garden by creating a small hole in a fence so frogs, toads, slow worms and other species, such as hedgehogs, can travel freely between your plot and neighbouring ones. Create a log or leaf pile, or a large open compost heap, where they can make a home.
Healthy soil produces healthy plants that are much more able to withstand slug damage – slugs tend to attack plants that are already weakened in some way. So mulch your garden with homemade compost, composted green waste or well-rotted manure to support healthy soil. If you don’t make your own compost, check out our comprehensive guide to getting started, which also includes a roundup of the best compost bins to buy.
How to Stop Slugs Eating Your Plants (100% Organic)
FAQ
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